Changing the Undo Tablespace to a Fixed Size

You change the undo tablespace to a fixed size to prevent the tablespace from growing too large or to better support Oracle Flashback operations. You can use Oracle Enterprise Manager Database Express (EM Express) to change the undo tablespace to a fixed size.

Note:

Only bigfile tablespaces can be changed to a fixed size. However, individual datafiles for a smallfile tablespace can be changed to a fixed size. See "Changing the Datafiles for an Undo Tablespace to a Fixed Size" for instructions for changing individual data files for a smallfile tablespace to a fixed size.

To change the undo tablespace to a fixed size:

In EM Express, go to the Undo Management Details page, as described in "Viewing Undo Information".
After determining the minimum required undo tablespace size, click the link after the Name field in the Tablespace section.

The Tablespace page appears, with the undo tablespace displayed.
Select the undo tablespace. Then from the Actions menu, select Resize.

The Resize Tablespace page appears.
In the File Size field, enter the computed minimum size for the undo tablespace.

See "Computing the Minimum Undo Tablespace Size Using the Undo Advisor".
Click OK.

A confirmation message appears.